System for the Measure of Thermal Properties of Fluids

ABSTRACT

The present invention refers to a system, composed by mechanical and electronic components and by a resident software inherent to the system. The system for the mean of thermal properties of fluids is destinated to the measure of thermal properties such as diffusivity and effusivity, and from those values, to obtain the conductivity and the volume thermal capacity of flowing media. Besides the use for the direct measure of thermal properties, the referred system has application in the verification of the quality or of adulterations in fuels (octane and no conformity), fuel oils and lubricants, perfumes, foods, drunk, and working as humidity met gases. In these cases the essential feature is the correlation of the measure of thermal property and the quality parameter of the substance analyzed. The present invention can used in industries and laboratories.

The present invention refers to a system that uses photothermaltechniques to measure thermal properties of fluids by means of thepropagation and interference of thermal waves. An application of thisinvention is directly related to the fluids analysis. Not only thisapplication area, it is possible, by means of the measure of the thermaldiffusivity and/or thermal effusivity, for example, to use the referredsystem for the verification of the quality (octane) or adulteration infuels, perfumes, foods, not only working as a humidity and gases meter.

In a general way, photothermal phenomena are associated to 4 thermalproperties and an optic one, in other words, the thermal conductivity(κ), thermal diffusivity (α), thermal effusivity (ε), volumetric thermalcapacity (ρc) and the optical absorption coefficient (β). The thermaland optical characterization of a sample (solid, liquid or gaseous),consists directly or indirectly on a tool to interpretation orcorrelation to other phenomena or physical properties of interest.

The working principle of the present invention is based on thepropagation of thermal waves in a medium. The thermal waves concept, aswell as its application, are already consolidated and used. They can bementioned as example the methods and apparatuses used for thecharacterization of solid materials according to the references of EP0163466A2, EP 0162681A2, EP 0102730A2, U.S. Pat. No. 4,690,569, U.S.Pat. No. 4,484,820, EP 0165711A2 and U.S. Pat. No. 4,513,384.

According to the invention, the basic working principle of the systemfor thermal properties measurement of fluids consists in generating, bymeans a of “thermal waves generator”, thermal waves front of impulse,step or periodic shape with frequencies can be set from 0.1 to 1000 Hz,that is generates from a surface, which may be preferably a thinmetallic disk. In order to a thermal waves front can be produced, it isnecessary that the disk receives a thin layer of a highly absorbentlight coating just as it is “black of the soot”. Not only this, togenerating the thermal waves is necessary that the modulated radiationimpinges on the blackened face.

Parallel located at the distance (L) in front of the surface of thethermal waves generator disk which is without covering, exists anothersurface, a disk, preferable made of β-polyvinyldielene fluoride (PVDF)metallic film. This pyroeletric film can detect temperature ripples of10⁻⁶K by the measuring of the alternated potential difference thatappears between the metallic faces, and whose amplitude is function ofgeometric and electric parameters of the film and of the spatial averagedistribution of the temperature on it surface. According to theinvention, the pyroeletric disk film not only working as a sensor, butit works also as a wall that partially promotes the thermal wavesreflection turning back to the disk that generated them. For example,for a given frequency (f), and for a certain distance (L) located in therange from 0 to 5 mm, it can happen overlap of the thermal wavesgenerated with the reflected thermal waves.

The theoretical expression of the signal generated on the sensor is$\begin{matrix}{{{S\left( {K,\Gamma,L,\alpha,f} \right)} = {K\frac{{\mathbb{e}}^{{- \sigma}\quad L}}{1 - {\Gamma\quad{\mathbb{e}}^{{- 2}\quad\sigma\quad L}}}}},} & \lbrack 1\rbrack\end{matrix}$where K is a complex constant that depends on electric parameters of thepyroeletric film and of the measure circuit parameters; L is thedistance between the pyroeletric sensor and the thermal waves generator;σ=(1+i)√{square root over (πƒ/α)}, ƒ is the frequency of the thermalwaves generator and α is thermal diffusivity of the medium.

The parameter √{square root over (πƒ/α)} is denominated thermaldiffusion length (μ) and physically it represents the effective depthpenetration of a thermal wave in a material or medium. The factor Γ, inthe expression [1], is the normal incidence reflection coefficient ofthermal waves that includes relationships among the thermal effusivityof the flowing medium, of the sensor pyroeletric and of the diskmaterial. Therefore, by means of the variation of the distance L and afixed thermal wave frequencey f, t is possible to acquire experimentalvalues from the signal of the sensor. By means of the statisticalcomputational fit of the theoretical expression [1] to the measuredpoints, it is obtained the value of the diffusivity (α) and of theeffusivity (ε) and consequently the one of the thermal conductivity (κ)and the volumetric thermal capacity (ρc) of the flowing medium.

In general, the signal levels involved in the measuring of theseproperties are very low intensity and they need an especial kind ofprocessing.

In the practice, the circuit, instrument or software that performs thisfunction is called synchronized amplifier (lock-in amplifier). Currentor voltage signal measured by means to this technique, can becharacterized by they values in phase and in quadrature (real andimaginary parts) or in amplitude (module) and phase. Both ways can beused to exhibit the signal graphics. More details can be seen in theworks: On The Uses Of The Thermal Wave Resonator Cavity Sensor ForMonitoring Hydrocarbon Vapors J. A. P. Lima, E. Marin, M. G. da Silva,M. S. Sthel, S. L. Cardoso, H. Vargas and L. C. M. Miranda Rev. Sci.Inst, 71, 7 (2000)., Characterization Of The Thermal Properties Of GasesUsing Thermal Wave Interferometer J. A. P. Lima, E. Marin, M. G. DaSilva, M. S Sthel, D. U Schramm, S. L Cardoso, H. Vargas And L. C. M.Miranda Meas. Sci. Technol, 12, 1949-1955 (2000), Measurement Of ThermalProperties Of Liquids Using Thermal Wave Interferometer J. A. P. Lima,E. Marin, O. Correa, M. G. da Silva, S. L. Cardoso, C. Gatts, C. E.Rezende, H. Vargas and L. C. M. Miranda Meas. Sci. Technol. 11 1522-1526(2000).

The present invention, uses preferentially the method called “made easy”for measuring thermal diffusivity of fluids. This method uses all of thephysical and theoretical elements of the previous method. The “madeeasy” method do not needs a continuous sweeping of the distance L,between the generator and the sensor to perform the measuring. Not onlythis characteristic, on the “made easy” method, the continuous recordingof the sensor signal V_(N) as a function of the time, results in acontinuous recording of a thermal property as a function of the time.Therefore, the thermal diffusivity for the statement method is given bythe expression:${\alpha = \frac{\alpha_{air}}{\left\lbrack {1 - \frac{\ln\quad V_{n}}{L\left( {\pi\quad{f/\alpha_{air}}} \right)}} \right\rbrack}},$in which α_(air·) is the thermal diffusivity of the air, V_(N) is thenormalized signal obtained during the measuring, L is a fixed distancekeeps between the sensor and the thermal waves generator, f is themodulation frequency the of thermal waves generator. This method isshown in more details in: Monitoring Of Gas Diffusion In Air Using TWITechnique: Thermal Diffusivity Measurements Made Easy J. A. P. Lima, M.G. Da Silva, M. S. O. Massunaga, S. L. Cardoso, E. Marin, H. Vargas AndL. C. M. Miranda Rev. Sci. Inst, 74, 1 (2003).

According to the present invention, It also exists the possibility of tobe performed in the system for thermal properties measurement of fluids,another measurement mode with the such system, in other words, it is thepossibility of substituting the thermal waves generator disk for a verythin laminule that be transparent to the exciting radiation range of thesource or laser. Unlike what it happens in the aluminum diskconfiguration, the laser beam crosses the transparent laminule reachingdirectly the whole area of the sensor. In this case, the thermal wave isgenerated on the sensor surface and not on a thermal waves generatordisk surface. In those conditions, the thermal property that influencesthe sensor signal is the thermal effusivity and not the thermaldiffusivity.

According to the present invention, an another configuration using thesame elements of the previous method, it can perform a selectivemonitoring of specific substances by means of the appropriate selectionof the wavelength of the light source or laser. Not only the appropriateselection of the wavelength it is also necessary to select anappropriate frequency of modulation so that the signal of the sensor, beonly sensitive to the optical absorption coefficient of the measuredsubstance (liquid or gas). This way, the concentration of the substanceunder interest can be monitored.

Established the theoretical principles, for the purposes of illustratingthe invention, there are shown in the drawings forms which are presentlypreferred, it being understood, however, that the invention is notlimited to the precise arrangements and instrumentalities shown.

FIG. 1 shows the front view of the system, on what it can be seen outthe display, the control panel, the analysis chamber as well as themovable probe and the prethermalizador device.

FIG. 2 shows the analysis chamber (A.C) and their respective parts.

FIG. 3 shows the parts that compose the system of thermal stabilizationof the chamber (S.T.S.C).

FIG. 4 shows the sample holder (S.H).

FIG. 5 shows the thermal waves cannon (T.W.C).

FIG. 6 shows the thermal waves sensor (T.W.S).

FIG. 7 shows the sample prethermalizador device (S.P.D).

FIG. 8 shows the system of measure and control (S.M.C).

FIG. 9 shows the microprocessing system (M.S).

FIG. 10 shows the movable probe (M.P).

FIG. 11 shows the operation diagram flow.

With reference to FIG. 1, the disk drive is shown (1); indicative pilotlamp of energized system (2); screen (3); prethermalizador/sample holdertemperature display (4); laser diode current/voltage display (5);analysis chamber temperature display (6); flashing LED to inform theprethermalization temperature is reached (7); LED (bicolor) to informthe temperature controller activity of the sample prethermalizatordevice (8); LED (bicolor) to inform the temperature controller activityof the sample holder (9); sample holder standby indicative LED (10); LEDto inform the laser diode power supply is enabled (11); flashing LED toinform the laser diode modulation is turned on (12); LED (bicolor) toinform the temperature controller activity of the system of thermalstabilization of the chamber (13); momentary button to make availablethe sample prethermalizator device temperature on theprethermalization/sample holder temperature display (4) (14); on/offswitch of the sample prethermalizator device's Peltier (15); on/offswitch of the sample holder's Peltier (16); potentiometer for adjustingthe sample holder temperature (17); momentary button to make availablethe laser diode voltage on the current/voltage display (5) (18);potentiometer for adjusting the polarization current of the laser diode(19); on/off switch of the laser diode modulation of (20); potentiometerfor adjusting the analysis chamber temperature (21); on/off switch ofthe analysis chamber's Peltier (22); switch to enable the movable probeor the analysis chamber (23); retractable keyboard (24); socket for thesample holder plug (25); socket for the thermal wave cannon plug (26);socket for the sample holder movable recipient thermocouple plug (27);on/off switch of the system of thermal stabilization of the chamber'spump (28); sample pretermalizador device (29); on/off switch of theanalysis chamber's exhaustor (30); sample holder (31); thermal wavescannon (32); hoses for circulation of thermal stabilization fluid (33);handle of the sliding door for access to the internal micrometer or tothe distance reference stems (34); analysis chamber (35); movable probe(36).

The following detailed description is of the best presently contempledmode of carrying out the present invention, This description is notintended in a limiting sense, but is made solely for the purpose ofillustrating the general principles of the invention.

According to a not limited mode of carrying out the invention, theanalysis chamber 1, FIG. 2, is composed by a flask 37, madepreferentially of transparent glass, in “T” shape, with double wall 38for the circulation of a fluid for thermalizing. At the two extremitiesof larger diameter of the flask, two rings are glued 39 and 40, whichare endowed with grooves to the fit in the borders of the glass part.Interconnecting the two rings, there are 4 steel stems (they are notvisible in the drawing), whose purpose is to assure the parallelismamong these rings and to prevent that the glass part be broken bycompression excess during the it fixation. The flask is maintainedfastens in it position by means of 4 nuts 41 and 4 fixation screws 42(only one of the nuts and one of the screws is visible in the drawing).On the periphery of the ring 40 are 2 adapters 43 and 44, in which theyare connected to the hoses that drive the thermalization fluid. In thissame ring, there is a valve screw (45) and a drain (46) for the passageof air and excess of thermalization fluid during a load or dischargeprocedure. Glued on the inferior opening of the flask, there is a ring(47) endowed with a “O” ring (48) and clamp pins (49) to fitting in thesample holder. The flask can be made of several materials, butpreferably was used the aluminum to making the rings, and the glass, forits low residues adherence. This assembly, not only allowing thecontinuous visualization of the state of the cannon and of the sensor,but it facilitates the cleaning for the user.

According to the invention, the chamber is also composed by a subsequentflange (50), preferentially made of aluminum, having one channel,through which the thermal waves cannon is introduced and locked by meansof one screw (51). The flange possesses 4 holes for the passage of thefixation screws (42) (only one of them is visible in the drawing), and ascrew valve (53) (V1) for relief of the pressure inside the chamberduring the placement or removing of the sample. This valve may beautomated by means of solenoid for the user's larger convenience.

The such chamber, possesses still a second flange (54), having 4 holesfor the fixation screws, whose function is the global support of thewhole array. This flange possesses a central channel through whichpasses and it slides the cylindrical body of the thermal waves sensor.On the second flange there is a screw valve (55) (V2) with the purposeof obstructing the passage between the internal chamber atmosphere andthe pipe that it is connected to the vacuum pump for cleaning thechamber. The connection is made by means of an adapter (56) whosechannel is extended to the interior of the chamber. This valve may bealso automated by means of solenoid for the user's larger convenience.

According to the invention, the analysis chamber is a totallydismountable device whose purpose is to provide an isolated atmosphereand constant volume. The effective volume of the chamber may be between50 to 1000 ml, preferentially a volume of 80 ml was used. The analysischamber is the place inside of which is performed the analysis ofsamples such as: mixture of air with volatile liquids vapor, gases,steams or exhaled gases from solids and liquids. With some adaptationsand modifications, the chamber may be flooded with the liquid to bemeasured. In some cases, it can have interest in measuring substancesunder higher pressures than one atmosphere, or under an initial vacuumcondition or of rarefied atmosphere. That is possible, as long as thestructure of the chamber and their associated parts are reinforced.

According to a not limited mode of carrying out the invention, thesystem of thermal stabilization of the chamber, that it can be seen inFIG. 3, consists of a pump 57, being preferentially of centrifugal type,of small size, and to using in DC; a reservoir 58, fastened by means ofscrews (59) and (60), preferentially made of copper, squared shape, withpipes for entrance and exit of liquid; a radiator (61) being preferablyrectangular and of aluminum, having fins (62); a fan (63) beingpreferentially of 12V DC, fastened by means of 4 screws (only the screws(64) and (65) they are visible); one Peltier element (66) beingpreferentially square, and hoses (67) for the circulation of the fluid.

According to the invention, the system of thermal stabilization of thechamber is based on a closed circuit of forced circulation of fluid bymeans of pump and transported by means of hoses. The efficiency of theradiator is improved by the forced passage of air through the fins ofthe radiator. The used fluid may be a mixture of etilen glicol withwater or water pure only. The purpose of such system is to maintainconstant the temperature inside the chamber's wall and also to createthe favorable conditions of humidity necessary for determined types ofmeasure.

According to a not limited mode of carrying out the invention, thesample holder, shown in FIG. 4, consists of a support (68) withcylindrical shape similar to a flange. This part, preferentially made ofteflon, works as a guide that allows the alignment of the movablecontainer of the sample holder (69) with the opening of the chamber. Thesupport (68) possesses a circular groove for a “O” ring (70) and a lowsquared relief with windowsill. This low relief is for the insertion ofa Peltier element (71), that it is the responsible active element forthe thermal stabilization of the sample.

Another part of the sample holder is a ring (72) which is madepreferentially of aluminum and that it is fit to the part (68),involving it. This part possesses two rifts (73) diametrically opposed,being adjusted to the two pins in the periphery of the opening of theanalysis chamber, allowing to the user the fast setting of the sampleholder on the measure position. The such part possesses a lateral pipeof exit (74) for the passage of the Peltier element's wires, thethermocouple's wires, the fan's wires and the wire of the detectioncircuit of the sample holder in the measure position.

The sample holder also possesses a circular tablet (75), preferentiallymade of copper, and having a channel of 2 mm of diameter that extends tothe center. The tablet works as a middle of thermal contact between thebottom of the movable container and the element Peltier, not onlyhousing a thermocouple inside of the channel of 2 mm, whose signal issent to the circuit of the temperature controller.

In the such sample holder, there is a cylindrical radiator (76), endowedof fins, on the upper region exists a circular high-relief over whichthe surface of the Peltier element is attached by means of a thermalpaste. Inside the part, and among the fins, exists a low relief withsquared shape, whose purpose is to accommodate a mini-fan (77) that itforces the circulation of air through the fins of the radiator. In thebottom of such part there is a protection screen (78) for the fan. Allparts are kept fasten by means of 4 screws (only the screws (79) and(80) are visible in the drawing).

According to the invention, the sample holder is the device that itworks as support of the movable container that containing the sample.The movable container has capacity to receive 10 ml of liquid sample andit may also receive solid samples. The sample holder also allows theseal of the internal atmosphere of the analysis chamber and the ambientair. Not only of those functions, the sample holder provides the thermalconditioning of the sample during a measure, and keeping it in aconstant temperature. This constant temperature can have two values. Alltime in which the sample is in the standby position, in others words,disconnected of the chamber, the movable container of the sample holderis maintained in a fixed temperature that can be the same one of theprethermalizador device and that it is adjusted by the user by means ofa precision trimpot embedded in the back panel. When the sample holderis connected on the chamber, automatically the controller receives acommand and it adjusts the temperature of the sample holder for a newvalue that is softwaremed by the user by means of a potentiometer ((17)FIG. 1). The sample holder is also provided of cable with connector,allowing this way the connection to the lateral front panel of thesystem ((25) FIG. 1). Therefore, it carries him/it sample as a whole isa replacement component, could be substituted in the complete by anotherone.

According to a not limited mode of carrying out the invention, thethermal waves cannon, FIG. 5, consists of a tubular body (81) in whoseinterior lodges a small laser diode cannon (82) endowed with lens forfocalization. The cannon laser diode is introduced through the backopening that receives a protection cover (83) that is locked by means ofa screw (84). The front opening of the cannon is covered with thethermal waves disk (85). The such disk may be made preferentially of a0.015 mm thickness commercial aluminum foil stretched and glued on theborder of a aluminum ring. The face of the disk gone back to theinternal part of the pipe must receive a thin layer of black coveringwith high optical absorption. Preferentially the covering should be theblack of the soot since this material possesses the highest opticalabsorption coefficient.

According to the invention, the thermal waves cannon has as function togenerate the thermal waves necessary for performing the measures. Thegenerated thermal waves depend on the form of wave of the current(sinusoidal, square, step or impulse) that is sent for the laser diode,or excitement source, or of heating, and depends on of the frequency andof the focus. The thermal waves cannon can generate frequencies from 0.1to 1000 Hz, but for most of the cases involving measures of vapors andgases, the preferential frequency to be used is of 10 Hz. Not only this,it is necessary that the focus be adjusted in order to illuminate allblack area of the disk of aluminum. The purpose of this fitting is toinduce the generation of plane thermal waves front. The assembly typesuggested here for the generator disk provides the easy removal and thesubstitution of the same in case of flabbiness, perforation oraccumulation of residues. The thermal waves cannon is also provided aconnector cable allowing its connection to the lateral front panel ofthe system (26 FIG. 1). Therefore, the thermal waves cannon as a wholeis a replacement component, and may be substituted entirely by ananother one.

According to a not limited mode of carrying out the invention, thethermal waves sensor in FIG. 6 is constituted of a body, preferentiallymade of brass (86), whose extremity is adapted to a circular head (87)that is constituted of several other components. The circular headpossesses two disks made preferentially of fiber printed circuit boardand that are fixed each other by means of 3 screws and 3 nuts (only thescrews (88), (89) and the nuts (90), (91) are seen in the drawing). Thefirst disk (92) is fastened to the brass body. The second disk (93)(frontal) possesses the same diameter and thickness of the first one,however, it differs of the other one for the fact of possessing a widecentral hole (94) and a conductive track of copper (95) for electriccontact with one of the metallic faces of the disk of PVDF (pyroeletricsensor) (96). In contact with the other metallic face of the disk ofPVDF, exists a brass pin (97) soldered to the output connector by meansof a wire (98). The electric loop of the circuit is made by means of athin ground wire soldered in the derivation (99) of the trail (95) ofthe front disk (93), passing through the chamfers (100), and that is asoldered to the body of the sensor (86). After the circular head (87),the borders of the disks, the areas around of the screws heads, nuts,periphery of PVDF and soldering points of the ground wire, be assembled,they should receive a impermeable protective resin. Glued on the finalextremity of the sensor there is a connector (101) with a thread typeconnection. Another part exists (102), with a embedded female typeconnector (103) which is soldered to a cable (104) and connected to themeasure circuit. This part allows the adaptation of the sensor to amicrometer head. The micrometer head type have to be of a non rotativespindle type in order to avoid the rotation of the cable during thedistance fitting.

According to the invention, the sensor is the component whose functionis to pick up the thermal waves, which is generated by the cannon and toconvert them in a correspondent electric signal. The electric signalwhen measured, translates it in a greatness that is sensitive to thevariation of the thermal property of the measured substance. The maincomponent of the sensor is a material pyroeletric. For use in thepresent invention, the preferential material is the β-polivinylidendifluoret (PVDF). The main characteristic of the b-PVDF is its easy cutin any format, not only it, but it presents a weak piezoeletriccomponent in relation to the pyroeletric one. Some ceramic materials arealso pyroeletric as the barium titanate and the zirconate lead titanateand alternatively, they may be used. The possibility of using amicrophone as detector can also be another alternative. Depending on thefrequency with that the sensor is exposed to gaseous or liquidaggressive substances or even for continuous exhausting use, the sensorwill need to be replaced. The connector type suggested in the presentinvention allows to the users of the system to substitute the sensoreasily for an another new one. Therefore, the sensor as a whole is asealed replacement component, and must be completely replaced for otherone in case of damage, bad operation or wear and tear.

For the necessary positioning of the sensor in relation to the thermalwaves cannon, in fact, there is no need that the micrometer have to bedigital, however, some of those models possess digital data output. Inthis case, it is possible to send them for the CPU of the system. Infact, for the present invention it can spare the inclusion of amicrometer, as long as there is some type of reference cursor by meansof which the distance between the sensor and the thermal waves cannoncan be adjusted accurately and maintained stable.

According to a not limited mode of carrying out the invention the deviceprethermalizador FIG. 7, consists of a metallic base (105) endowed withfins. Among the fins, a space exists where a mini fan is embedded (106).On the such base, a Peltier element (107) is attached and is fastened bymeans of thermal paste. Involving the element Peltier, a foam blockexists for thermal isolation (108) that adapts to the outline of thestatement element. The foam block is fastened to the base (105) by meansof glue. Around of the circular opening of the foam and of the cover(109), two metallic rings exist (110) and (111) soldered each one in athread. The device is endowed with movable container (112) with capacityto receive 20 ml of liquid sample. The container is inserted in itsreceptacle (113). Inside the cover a thermocouple exists (114) which isin direct contact with the liquid sample.

According to the invention, the prethermalizador device makes thethermal conditioning of a sample before it to be put in the sampleholder and to be taken to the chamber for the accomplishment of ameasure. The prethermalization process only has beginning when the coveris put on the movable container. The cover (109) that is put on himreferred movable container avoids the exhibition of the sample to theatmosphere during the prethermalization process. The rings (110) and(111) work as an electric key for automatic activating of theprethermalization process. The thermal conditioning is necessary toguarantee that all of the samples, for a certain measure type, be in thesame initial condition of temperature before they be taken for thechamber. The reference temperature that must be maintained constant bymeans of the temperature controller is the temperature of the surface ofthe liquid contained in the movable container. The prethermalizadordevice also possesses a cable with connector in its extremity toconnecting to the back panel of the instrument. The prethermalizadordevice as a whole, is a replacement component and so may be substitutedcompletely by an another one.

According to a not limited mode of carrying out the invention, themeasure system and control, FIG. 8, becomes separated in 7 blocks.

The first block (115) consists of a transimpedance pre-amplifier thatcan be based on the integrated circuit TI 081. The function of thiscircuit is to amplify the low signal of originating from current thesensor or of the movable probe and to turn it compatible with the stageof synchronous detection.

The second block (116) consists of a synchronous detector. The basiccomponents of this healthy detector: filter band pass (116 a),multipliers (116 b), sinusoidal generator (116 c), generator cossenoidal(116 d) and raisin-low filters (116 e). The circuit for this detectorcan be based on the integrated circuit AD 534 that is an analogicalmultiplier of precision. The sinusoidal generators and cossenoidal canbe implemented with a digital accountant, converter D/A and memoirsEPROM. The filters can be based on the integrated circuit TL 084. Themodule extractor and angle can also be implemented also with AD 534,EPROM and converter D/A. The synchronous detecting block is alsosusceptible to be implemented by means of a software that receives themeasured values by means of a circuit or plate A/D. It still exists thepossibility of the use, for example, of a detecting commercial platesynchronous of the type OL 4000 for PC. In these last two options, thesynchronous detector stops belonging to the measure system and controland raisin to do part of the microprocessamento system.

The third block (117) consists of the temperature controller. This blockis composed by 3 controlling circuits of temperature (117 a), (117 b)and (117 c) based on the integrated circuit AD 590 that converts thevoltage of a thermocouple directly in a voltage proportional to thetemperature of the process to be controlled. That voltage is comparedthen with the softwareming temperature by means of a voltage comparatorusing an integrated circuit TI 081. Of this it sorts things out, thevoltage resulting from the comparison is sent for a power driver thatfeeds directly the Peltier element. The 3 circuits are independent,being each one for each function, in other words, to control thetemperature of the sample holder A, of the device prethermalizador B andof the system of thermal stabilization of the chamber C.

The fourth block (118) it consists of a source/modulator whose functionis the feeding and modulation of the diode laser. The source for feedingof the diode laser is of the constant average type whose circuit isbased on the integrated circuit TL 081 and in the transistor TIP 122.The circuit of the source should possess devices of safety such an as:

-   -   The increase of the current should be made by means of a        multi-turns potentiometer (or equivalent electronic circuit that        it allows soft variation) in order to avoid her burns accidental        of the diode laser for abrupt ascent of the current.    -   To impede the activating of the laser after a lack of energy of        the net electric case the potentiometer (or electronic circuit)        it has been left in a value of larger current than 1% of the        maximum current.

As modulator of the diode laser, in this case, a transistor TIP 122 wasused to drain cyclically the current of the diode laser for the earth.The form of chosen wave for the modulation of the diode laser was thesquare wave. The wave, injected in the base of the transistor, it isgenerated by a softwaremable oscillator to crystal of quartz based onthe frequencey divisor integrated circuit NE 4059.

The fifth block (119) it consists of 3 display panels cases with 3½digits. Such display cases can be liquid crystal or of LED. In bothcases, they can be implemented with the circuits integrated CI 1705 orCI 1706, or they be acquired in commercial modules already ready forinstallation and use.

The sixth block (120) it consists of a vacuum pump, preferentially ofdiaphragm and of continuous current 24V, whose purpose is to renew theair of the chamber contaminated by the last measured sample. The pump isconnected to a circuit electronic timer that turns off it automaticallyin 5 minutes after it being worked by the user.

The seventh block (121) it consists of a exclusive power supply,preferentially of the switched type, with multiple exits and withindependent fuses for each block of the referred measure system andcontrol.

According to the invention, the measure system and control is entrustedby all of the functions not computing involved in the measure of thermalproperties. The whole system is energized by means of an independentgeneral on/off switch, located in the back panel.

According to a not limited mode of carrying out the invention themicroprocessing system, FIG. 9, becomes separated in 7 blocks.

The first block (122) consists of a central processing unit that can becommercial board with bus type ISA/PCI, or microprocessed systemdedicated to accomplish the necessary functions to the operation of thesystem for measurement of thermal properties of fluids. In both cases,it owes if to have as minimum requirements: a processor of 133 MHz, 16Mb of RAM memory and hard disk with 100 Mb of memory. Preferentially theblock (122) it can be a commercial standard system MOP 104 that not onlybeing more compact, it can work with a hard disk (123) in solid stateavoiding the loss of the data this way in case the system suffers somefall type or impact.

The second block (124) consists of an unit for recording and reading ofdata for the external transfer or acquisition of the measures files ordata of the equipment. In this case the options can be a flexible diskdrive 3½″, Zip or of CD.

The third block (125) consists of a screen or monitor that it makespossible the clear visualization of the graphics exhibited by thesoftwares installed in the system. Preferentially the display can be ofthe type TFT 6×5″ colored that is compact, it presents excellentresolution and shine.

The fourth block (126) consists of a softwaremable mini-keyboard, thatshould have at least 44 keys and it can be of the type membrane or ofbuttons.

The fifth block (127) consists of a mouse, being indicate the typetrackball preferentially. In this case, the mouse can be built-in in theown keyboard. The other option is the use of a common mouse, linked tothe serial door of the plate CPU.

The sixth block (128) consists of a power supply of the type used in PC.This source being exclusive for this system, it impedes that anyinfluence type, interference or noise of the measure system happens.

The seventh block (129) consists of a plate or circuit with multipleentrances and analogical exits. This block is necessary only in themodalities of accomplishment of the system for measurement of thermalproperties of fluids in that the functions carried out by the measuresystem and control be executed by means of a software.

The eighth block (130) consists of a synchronized detection board. Thisblock is necessary only in the modalities of accomplishment of thesystem for measurement of thermal properties of fluids in that thefunction of synchronous detection, carried out by the measure system andcontrol, it be executed by means of a software.

According to the invention, the microprocessing system has as functionthe acquisition of the experimental data, processing, calculations,softwareming, introduction of data, exhibition of results and graphics,recording and reading of information that you/they are necessary to theoperation of the system for measurement of thermal properties of fluids.The system computational has a general on/off switch located independenton the back panel.

According to a not limited mode of carrying out the invention, themovable probe, FIG. 10, is constituted basically of a main cylindricaltube (131) in whose interior lodges a cannon of diode laser or radiationsource (132) with lens for focalization. A cover endowed with thread(133) it maintains closed the opening through where the cannon isintroduced. Screwed to the main cylindrical tube (131) a longersecondary tube exists (134) whose extremity is covered with thegenerating disk of thermal waves (135). This part can be madepreferentially with a disk of commercial aluminum foil of stretched andagglutinated 0.015 mm of thickness in the border of a ring of aluminum.The face of the disk gone back to the internal part of the tube shouldreceive a black covering with high optical absorption. Preferentiallythe covering should be the black of the tobacco. The making heresuggested for the generating disk provides the easy removal andsubstitution of the same in case of flabbiness, perforation oraccumulation of residues. Involving the longer secondary tube (134), aslippery tube exists (136), with restraint screw (137), possessing inthe subsequent extremity a disk with 3 willing stems in triangle (onlythe stems (138) and (139) they are visible). The said stems sustain thedisk (140) where the sensor film of thermal waves is set up and theyserve as a middle of passage of the threads of contact of the sensor ofthermal waves. The threads continue through a tube until they enter inthe main cylindrical tube (131). In order to avoid the exhibition of thethreads, a flexible folding hose of protection exists (141) that is fitin among the slippery tube (136) and the main cylindrical tube (131).Coupled to the slippery tube there is a disk of sensor element (PVDF)(141) that is housed among two disks (142) and (143) that are maintainedunited through 3 screws and 3 nuts which possess copper trails that workas contact electrodes (only the screws (144) and (145) and the nuts(146) and (147) they are visible). After the assembly of the sensorelement, a scouring pad is introduced (148), preferably done in teflon,with the purpose of stretching the sensor element so that this is with ahigh relief frontal. The scouring pad is fixed to the stems through 3nuts, and just the nuts (149) and (150) they are shown.

According to the invention, the movable probe is one of the devices thatcomposes the system for measurement of thermal properties of fluids. Thesaid probe is especially indicated for measures of thermal properties inliquid means, and depending on fittings, eventually it can be used formeasure in gases or vapor. The beginning of operation of the movableprobe is exactly the same described for the sensor and the cannon usedin the analysis chamber. The modulated light or pressed of a radiationsource it happens on the blackened surface of the generating disk ofthermal waves (135). The said waves cross the half liquid (or gaseous)and they arrive to the disk of sensor element (PVDF) (141). Theamplitude of the signal generated in the sensor is function of thefrequency of modulation of the radiation source, of the distance betweenthe sensor and the generating disk of thermal waves and of the thermaldiffusivity of the middle in that the probe is inserted. For most of thecases of measures of the thermal diffusivity of liquids, the spacingamong the sensor can be of the order of 1 mm and the frequency ofmodulation 1 Hz.

It is also possible to perform another measurement mode with the movableprobe by means of the substitution of the generating disk of thermalwaves (135) for a thin sheet that it is transparent for the strip ofradiation of the source of used excitement or of a laser. In this case,the thermal wave is generated in the own surface of the sensor (141) andnot by means of the generating disk of thermal waves. With thisconfiguration, the thermal property that it influences the signal of thesensor is the thermal effusivity and no the thermal diffusivity.

According to the invention, another configuration using the sameelements of the previous configuration, it can turn possible a selectivemonitoring of substances specify by means of the appropriate selectionof the wavelength of the luminous source or of a laser (132). Not onlythe appropriate choice of the wavelength it is necessary but also thechoice of a frequency of appropriate modulation, so that the signal ofthe sensor is just sensitive to the optical absorption coefficient ofthe liquid or of the measured gas. This way, the concentration of asubstance of interest can be monitored. Due to the fact of the saidprobe to possess small dimensions and a long connection cableinterconnecting it to the main system, the same can be handled easily bythe operator and to be taken or installed at some distant place of thesystem. Likely the other devices of the system, the movable probes as awhole, it is a replacement component and may be substituted completelyby another one.

So that the system for measurement of thermal properties of fluids toperforms the measurement of thermal properties, is necessary theexistence of a resident software containing an exhibition module thatmakes the acquisition of the measured values for the sensor and make thedue processing and calculations, whose results should be presented in anappropriate way for the user. According to a not limited mode ofcarrying out the invention, the said software can be created to workwith the operating system DOS, Windows or Linux, in case themicroprocessor system of the present invention uses a processing board,as for example, Pentium, Athlon, etc. The software can be developed inVisual language Basic. In this case, the resident software shouldexhibit a main screen that you/he/she is carried automatically someseconds after the power switch of the microprocessing system to becalled. The main screen should be presented in the form of a graphicscreen with horizontal and vertical graduation, exhibition boxes andmenu bar.

For the case in that the thermal property to be registered in functionof the time is the diffusivity, the horizontal axis of the graphicrepresents the time and the vertical axis, the thermal diffusivity. Theexhibition boxes are in number of 8 and they should show the name of thefile of the measure in process, the value of the instantaneous module ofthe signal of the detector (mV), the instantaneous value of the thermaldiffusivity (cm2/s), the value of the real component of the signal X(mV), the value of the component imaginary of the signal Y(mV), thevalue of the phase (degrees), the modulation frequency (Hz) and the time(s) elapsed of the measure.

The main screen of the software also owes disposal of a menu where theuser can access such options as: FILE, START AND CLEAR SCREEN. In theoption FILE it is available for the user a field nominated FOLDER, wherea series of titles is exhibited. The titles of those folders can betyped in another field denominated NEW FOLDER. Whenever possible, thetitles should be chosen in way do her allusion to the nature, origin orto the substances whose files of measures in them are contained. When afolder is selected by the user, the list of the files in her containedit should be visible in a field denominated LIST OF FILES. In the spaceof another field denominated NEW FILE, a new file can be typed andincreased to the LIST OF FILES. In another field, still inside of theoption FILE, it should have an option denominated COLORS, in case thescreen is colored, and SYMBOLS, in case the screen is monochrome. Theexistence of such functions has for objective to allow to the user thechoice of the color or symbol with that a certain file or files for theywill be shown in the screen. Linked to the option FILE should be thecommands: SAVE, DELETE, LOAD GRAPHIC AND CLEAR GRAPHIC.

Still in the menu it should have an option denominated CONFIGURATIONS.In this option the user can configure the interval of time between theacquisitions of the points of the measure, the total time of duration ofthe measure, the inferior limit and the superior of the vertical scale.

All of the functions previously mentioned here are considered as minimumrequirements so that a measure is accomplished, exhibited in real timeand stored. After all of the previous parameters be configured by theuser, a measure can be accomplished following the flowchart of FIG. 11.

Another included module in the menu of options is a software forfitting. This software makes calculations and it adjusts with thesmallest possible deviation the points generated in a measure to amathematical model that can be introduced by the user, by means ofkeyboard, in a denominated field, MODEL. In the field MODEL, it can beinserted and stored an equation that includes a series of way parametersto describe the registered phenomenon. Also in the same field they canbe chosen the parameters that they will be exhibited in the vertical andhorizontal axis, and this way, to be made a correlation among theseparameters. The software FITTING, also includes an option PLOT, thatwhen worked, he/she draws in the screen the result of the model, makingpossible of this way, a visual comparison between the graphic of themeasure and the model made calculations by the software. For the casesof measure of steams of such volatile liquids with gasoline, alcohol,perfumes, etc, or whose model of variation of the thermal diffusivity isadjusted to the simple exponential curve, the methodology denominatedconformity” “grating described in the work Photothermal Detection ofadulterants in Automotive Fuels J. A. P. Lima, M. S. O. Massunaga, H.Vargas And L. C. M. Miranda Rev. Anal. Chem, 76, 114-119 (2004) itshould be used. For the exponential case, the software has the functionLEVELS. The function GRATING exhibits a screen and several options whereshe can select the several files stored that you/they will be used tocompose a certain grating. Should the screen also possess a box wherethe user types the value of the distance (GAP mm) between the generatorand the sensor of thermal waves (is the distance adjusted by means of amicrometer). In the making of a certain grating, they will only be ableto be used the measures that be accomplished for a same value of “GAP”.THE grating a delimited area of a graphic is whose vertical axisrepresents the constant greatness of decline τ (seconds) and thehorizontal axis, the greatness thermal diffusivity α (cm2/s). This way,for any measure of thermal diffusivity in function of the time that isadjusted to the exponential model, is possible to obtain a value of α(cm2/s) of saturation (value reach in the end of a measure) and constantof decline τ (seconds). In order to the pair or the several pairs ofvalues can be plotted in the screen, it is necessary first to select afile or files of measures, contained in the LIST OF FILES. After that,the function CALCULATE should be activated. The such function works aninteractive algorithm of fitting non linear, for example, of the typeMarquardt that adjusts the generic curve of a theoretical model to theexperimental points obtained in the measure. In case the exhibition of areport of all of the points α and τ calculated and plotted for thesoftware, a function HISTORIC should be offered. To clean the screenthere is the function to CLEAN SCREEN and to return to the mainsoftware, a function, QUIT.

For the making of a grating, the software has a function, to CALIBRATE.For statistics reasons, the software should only allow the calculationof a grating if the number of files of measures selected by the usergoes same or larger than 15. Graphically a grating is an squared area orrectangular whose borders are defined for statistical calculation thatit take into account the several pairs of values (α, τ) measured for anuniverse of substances of a same type.

To use the function CALIBRATE, it should first to select the files ofinterest and soon to work the function to CALIBRATE. After at the end ofthe calculation, it should appear on the screen a column with a seriesof empty spaces where the user can type a title, that preferably, makereference to the characteristics specify of that grating. Therefore, theinformation of the grating are memorized and they can be loaded later inthe graphic by means of the function GRATING. With this methodology, anynew measure of a substance can be tested in relation to a certainassociated grating a group of this same substance. This way, it can beverified the parameters α and τ of the substance in subject do locateinside or out of the said representative grating of the group ofsubstances for which the grating was built.

For the case of measures with the movable probe, all of the previousfunctions are valid.

1- SYSTEM FOR THE MEASURE OF THERMAL PROPERTIES OF FLUIDS, characterizedby constituting of a system for the measurement of thermal properties offluids, that it uses photothermal principles of generation and detectionof thermal waves and that it is composed by an analysis chamber, asystem of thermal stabilization of the chamber, a sampler holder, athermal waves cannon, a thermal waves sensor, a sample prethermalizatordevice, a system of measure and control, a microprocessing system, amovable probe and a resident software for processing and exhibition ofthe acquired data during a measure. 2- system for the measure of thermalproperties of fluids, according to the claim 1, characterized by beingthe analysis chamber composed of a flask, a flange of sustentation ofthe cannon and a flange of sustentation of the flask. 3- system for themeasure of thermal properties of fluids, according to the claim 2,characterized by being the flask preferentially made of transparentglass, for being in format of “T”, for possessing double wall, forpossessing three metallic rings, and the subsequent ring is glued on thesubsequent region of the flask, the previous ring is glued on theprevious region of the flask, and the inferior ring, with smallerdiameter, is glued on the inferior opening of the flask. 4- system forthe measure of thermal properties of fluids, according to the claim 3,characterized by being the subsequent ring preferentially made ofaluminum, for possessing a central hole for the fitting of the flange ofsustentation of the thermal waves cannon, for possessing two circularchannels for the fitting and collage in the subsequent part of the glasspart that compose the flask. 5- system for the measure of thermalproperties of fluids, according to the claim 3, characterized by beingthe previous ring preferentially made of aluminum, for possessing acentral hole for the fitting of the flange of sustentation of thechamber, for possessing two circular channels for the fitting andcollage in the subsequent part of the glass part that compose the flask,for possessing two holes with adapters for the connection of the hosesthat take and bring the fluid of thermalization of the chamber, forpossessing a valve screw and a drain for passage of air and expulsion ofthe excess of thermalization liquid during a purgative procedure or ofload. 6- system for the measure of thermal properties of fluids,according to the claim 3, characterized by being the inferior ringpreferentially made of aluminum, for possessing two horizontal pinsdiametrically opposed, for the clamp of the sample holder, forpossessing a circular channel for the fitting of a sealing ring. 7-system for the measure of thermal properties of fluids, according to theclaim 2, characterized by being the flange of sustentation of the cannonpreferentially made of aluminum, for possessing a central channel tohouse the thermal waves cannon, for possessing a lateral screw forlocking of the cannon, for possessing four holes ebb tides for thepassage of 4 fixation stems with endings in thread, for possessing avalve screw for relief of the pressure it interns of the chamber. 8-system for the measure of thermal properties of fluids, according to theclaim 2, characterized by being the flange of sustentation of the flaskpreferentially made of aluminum, for possessing a central channel whereis camped and the thermal waves sensor slides, for possessing four holeswith thread it interns for the adaptation of the 4 fixation stems withendings in thread, for possessing a valve screw to ban the passagebetween the access channel to the interior of the chamber and theconnected hose to the vacuum pump, for possessing an adapter in theentrance of the passage between the access channel to the interior ofthe chamber, for the connection of the hose of the vacuum pump. 9-system for the measure of thermal properties of fluids, according to theclaim 1, characterized by being the system of thermal stabilization ofthe chamber a closed system of liquid circulation and with forceddissipation by circulation of air, being constituted by a reservoir,hoses, a pump, an Peltier element, a radiator and a fan. 10- system forthe measure of thermal properties of fluids, according to the claim 9characterized by being the reservoir preferentially made of copper, forbeing of squared shape or compatible to the form and area of the Peltierelement to it coupled, for possessing a narrow channel to house athermocoupler that is connected to the temperature controller of thesystem of thermal stabilization of the chamber, for possessing entrancepipes and liquid exit for adaptation of hoses, for being coupled to thePeltier element through a thermal paste, for being wrapped up in a foamshirt for thermal isolation that copper all of the lateral surfaces,except that that is in contact with the face of the Peltier element. 11-system for the measure of thermal properties of fluids, according to theclaim 9 characterized for they be the hoses preferentially made ofthermal insulating material and for they be a medium of transport ortransport so that the thermal stabilizant liquid goes by all thecomponents involved in the thermal stabilization of the chamber. 12-system for the measure of thermal properties of fluids, according to theclaim 9 characterized by being the pump preferentially centrifuge and ofcontinuous current. 13- system for the measure of thermal properties offluids, according to the claim 9 characterized by being the Peltierelement the device that it makes the heating or the cooling of theliquid for the thermal stabilization of the chamber and for being workedthrough a temperature controller. 14- system for the measure of thermalproperties of fluids, according to the claim 9 characterized by beingthe radiator a solid block, preferentially made of aluminum and withrectangular shape, for possessing in one of the faces a compact groupwith several parallel fins of dissipation, for possessing in theopposite face the one of the fins a low relief for the fitting of thePeltier element, and for possessing two holes for the reception of thescrews of fixation of the reservoir. 15- system for the measure ofthermal properties of fluids, according to the claim 9 characterized bybeing the fan of continuous current, to be without brushes, to belocated above the dissipation fins in order to produce the forcedpassage of a flow of air, for being arrested through screws that passfor among the fins and that you/they are screwed to the block radiator.16- system for the measure of thermal properties of fluids, according tothe claim 1, characterized by being the sample holder composed of ametallic support, a cylindrical support, a copper disk, an Peltierelement, a cylindrical base, a fan and a protection screen. 17- systemfor the measure of thermal properties of fluids, according to the claim16, characterized by being the metallic support preferentially made ofaluminum, to be fit in by pressure to the cylindrical support, forpossessing a lateral tube for the exit of the threads of the internalelectric devices of the sample holder. 18- system for the measure ofthermal properties of fluids, according to the claim 16, characterizedby being the cylindrical support preferentially made of teflon, to befit in by pressure to the ring of aluminum, for possessing a circularchannel for the fitting of a luting ring, for having a low relief foradaptation of the copper disk, for maintaining the united group throughthe 4 screws that go by the holes of fixation of the fan. 19- system forthe measure of thermal properties of fluids, according to the claim 16,characterized by being the disk of leaning copper to the cylindricalsupport for the superior and leaning face to the Peltier element by theinferior face, for sustaining the bottom of the movable container of thesample holder, for possessing a narrow channel that extends from theperiphery to the center, with the purpose of a thermocoupler that isconnected the temperature controller of the sample holder camping. 20-system for the measure of thermal properties of fluids, according to theclaim 16, characterized by being the Peltier element the device that itmakes the heating or the cooling of the sample, for being worked by atemperature controller, for being leaning for the superior face to thecopper disk and leaning for the inferior face to the high relief of thecylindrical base. 21- system for the measure of thermal properties offluids, according to the claim 16, characterized by being thecylindrical base preferentially made of aluminum, for possessing a highrelief for the support of the Peltier element, for being endowed withdissipation fins with a central cavity for the embeddement of a fan. 22-system for the measure of thermal properties of fluids, according to theclaim 16, characterized by being the fan of continuous current, to bewithout brushes, for being embedded in a cavity among the dissipationfins in order to produce the forced passage of a flow of air, for beingarrested through screws that pass for among the fins and they arescrewed to the block radiator. 23- system for the measure of thermalproperties of fluids, according to the claim 16, characterized by beingthe protection screen in striped form, in way to not to minimize theeffect of suction of air and in order to impede that any object or theuser's hand plays in the helix in rotation. 24- system for the measureof thermal properties of fluids, according to the claim 1, characterizedby being the thermal waves cannon constituted by a tubular body, agenerating disk of thermal waves, a protection cover and for a modulableradiation source. 25- system for the measure of thermal properties offluids, according to the claim 24, characterized by the fact of thetubular body to be made preferentially in brass, for possessing atraverse section of larger diameter for the lodging of the modulableradiation source that is contained by a protection cover, for possessinga traverse section with smaller diameter for the adaptation of thegenerating disk of thermal waves. 26- system for the measure of thermalproperties of fluids, according to the claim 24, characterized by beingthe preferentially made of aluminum, to be covered on the face thatreceives the incidence of the radiation, with a fine layer of a materialwith the largest coefficient of possible optical absorption. 27- systemfor the measure of thermal properties of fluids, according to the claim24, characterized by being the protection cover made of brass, for beingcoupled to the part previous of the tubular body, for being lockedthrough a screw, for possessing a hole for the passage of the cable offeeding of the source radiation modulable. 28- system for the measure ofthermal properties of fluids, according to the claim 24, characterizedby being the source radiation modulable a small cannon with a diodelaser or LED of high brightness, endowed with focalization lens, or forbeing an incandescent mini-lamp, or to be based on the direct heatinggenerated by a connected resistance to a variable source, or for athermoelectrical element (Peltier) that is in direct contact with theblackened surface of the generating disk of thermal waves. 29- systemfor the measure of thermal properties of fluids, according to the claim1, characterized by being the thermal waves sensor constituted of acylindrical body, a circular head, a sensor element of thermal waves, anending connector and an adapter for micrometer. 30- system for themeasure of thermal properties of fluids, according to the claim 29,characterized by being the cylindrical body preferentially made ofbrass, for possessing in the part it interns a longitudinal channel forthe thread passage, and for possessing in the previous extremity a holeendowed with thread for connecting of a connector of ending male type.31- system for the measure of thermal properties of fluids, according tothe claim 29, characterized by being the circular head, constituted bytwo disks circular overlapped, a previous one and the other subsequent,and that you/they are maintained united through screws and nuts. 32-system for the measure of thermal properties of fluids, according to theclaim 31, characterized by being the previous disk glued on theextremity of the cylindrical body, for being made preferentially from aprinted circuit board of copperless layer, for possessing a central holefor the passage and fitting of a brass electrode in tax shape, whose pinis soldered to a thread for the transport of the electric signal of thesensor element, for possessing three holes had in triangle for thepassage the fixation screws to the subsequent disk. 33- system for themeasure of thermal properties of fluids, according to the claim 31,characterized by being the subsequent disk made preferentially startingfrom a printed circuit board with only face of copper, for possessing awide central hole for the exhibition of the sensitive area of the sensorelement, for possessing three holes had in triangle for the passage thefixation screws to the previous disk, for possessing in one of the facesa copper electrode in form of a ring that accompanies the whole outlineof the wide central hole, for possessing the copper ring a lateralderivation in appendix form that extends from the border of the ring tothe periphery of the disk in the sense of the ray, and whose extremityis welded to the thread earth of the sensor element. 34- system for themeasure of thermal properties of fluids, according to the claim 29,characterized by being the sensor element preferentially a polymericfilm of β-polivinilideno difluoret. with pyroeletric properties, forbeing housed among the previous and subsequent disks, for could be usedalternatively in substitution of the polymeric film one ceramic materialjust as the barium titanato or the zirconate lead titanate, for also tobe used an eletret microphone alternatively. 35- system for the measureof thermal properties of fluids, according to the claim 29,characterized by being the ending connector adapted in the extremityprevious of the sensor, for being of the type thread male, whose pin issoldered to the thread that drives the signal of the sensor. 36- systemfor the measure of thermal properties of fluids, according to the claim29, characterized by being the adapter for micrometer a cylindricalpart, preferentially made of brass, that possesses in the subsequentextremity a channel where a female connector type thread is embedded,whose pin is soldered to the cable that drives the signal of the sensorto the pre-amplifier, for to possess in the previous extremity a channelof smaller diameter endowed with three traverse holes with thread forthe reception of fixation screws that you/they make possible this way,the joining of the group to the axis of a micrometer of the type spindleno rotative or to a device or reference cursor through which, thedistance between the sensor and the thermal waves cannon, it can beadjusted accurately and maintained stable. 37- system for the measure ofthermal properties of fluids, according to the claim 1, characterized bybeing the device prethermalizator of the sample constituted by ametallic base, a fan, a foam block, an Peltier element, two metallicrings and a cover. 38- system for the measure of thermal properties offluids, according to the claim 37, characterized by being the metallicbase preferentially made of aluminum, for being a support base forPeltier element, for being endowed with dissipation fins with a centralcavity for the embeddement of a fan, for possessing two lateral holes,one for the exit of a flexible cable with connector in the extremity andother for the exit of a linked flexible cable to the cover and forpossessing the said metallic base a foam block that is glued on thesuperior area no busy for the Peltier element. 39- system for themeasure of thermal properties of fluids, according to the claim 37,characterized by being the fan of continuous current, to be withoutbrushes, for being embedded in a cavity among the dissipation fins inorder to produce the forced passage of a flow of air. 40- system for themeasure of thermal properties of fluids, according to the claim 37,characterized by being the foam block preferentially of polyurethane forthermal isolation, for possessing a hole in the vertical sense for theaccommodation of the movable container containing the sample, forpossessing in the ending of the statement vertical hole an excavation inlow relief for the fitting and thermal isolation of the lateral part ofthe Peltier element. 41- system for the measure of thermal properties offluids, according to the claim 37, characterized by being the Peltierelement the device that it makes the of the sample through heating orcooling, for being worked through a temperature controller, for beingleaning in the metallic base for the inferior face and for supportingthe base of the movable container containing the sample to bepretermalized. 42- system for the measure of thermal properties offluids, according to the claim 37, characterized for they be the twometallic rings, the superior and the inferior, preferentially made ofbrass, for to be the agglutinated inferior ring to the foam block forthermal isolation of the Peltier element and being soldier to a threadthat is connected to the detecting circuit of closed cover, for beingthe agglutinated superior ring to the inferior part of the cover andalso to be to a thread that is connected to the detecting circuit ofclosed cover. 43- system for the measure of thermal properties offluids, according to the claim 37, characterized by being the coverconstituted by dense cylindrical block, preferentially made of brass,that possesses an internal lowering for accommodation to the superiorpart of the movable container, for possessing a channel for the lodgingof a mineral thermocoupler type whose stem stays immersed in the samplewhen the cover is closed on movable container, and for possessing aflexible cable for the passage of the thread of the superior ring and ofthe threads of the thermocoupler. 44- system for the measure of thermalproperties of fluids, according to the claim 1, characterized by beingthe system of measure and control composed by a pre-amplifier, asynchronous detector, 3 temperature controllers, a current/modulatorsource, 3 panel display cases, a vacuum pump and a feeding source. 45-system for the measure of thermal properties of fluids, according to theclaim 44, characterized by being the pre-amplifier of the typetransimpedance for the cases in that the sensor element is of theaverage type, for being of the type tension for the cases in that thesensor element is of the type tension, for being preferentially based onoperational amplifiers. 46- system for the measure of thermal propertiesof fluids, according to the claim 44, characterized by being thesynchronous detector constituted by a filter raisin-band whose exit isconnected to the entrances of two tension multipliers, and one of themultipliers multiplies the originating from signal the exit of the bandpass filter for a senoid generated by a sinusoidal generator, and theother multiplier multiplies the originating from signal the exit of theband pass filter for a cossenoide generated by a generator cossenoidal,the individual signal resulting from each one of the multiplications isapplied to the entrance of a raisin-low filter that suppresses tocomponent alternated resulting from the multiplication, resulting in oneof continuous current whose width is proportional to the width generatedby the sensor. 47- system for the measure of thermal properties offluids, according to the claim 44, characterized by being the 3independent temperature controllers, belonging one to them for thecontrol of temperature of the analysis chamber, other for the control oftemperature of the device prethermalizator and other for the control oftemperature of the sample holder, for they be preferentially based incontrol by closed mesh and PID. 48- system for the measure of thermalproperties of fluids, according to the claim 44, characterized by beingthe current/modulator source based in a circuit of source of constantcurrent for the feeding and modulation of the radiation source, forpossessing a frequency generator whose signal is applied to the currentsource in order to generate the necessary modulation for radiationsource. 49- system for the measure of thermal properties of fluids,according to the claim 44, characterized by being the 3 independentpanel display cases amongst themselves, preferentially of crystal liquid3½ digits, belonging one to them to exhibit the temperature of theanalysis chamber, other, with couple function, to exhibit alternately orthe current or the tension of the radiation source, and other withcouple function, to exhibit alternately or the temperature of the deviceprethermalizator or the temperature of the sample holder. 50- system forthe measure of thermal properties of fluids, according to the claim 44,characterized by being the vacuum pump used to make the renewal orcleaning of the analysis chamber after the accomplishment of a measure,for being preferentially of the type diaphragm, for being fed bycontinuous current and for being toggled by a circuit timer that turnsoff her automatically after 5 minutes. 51- system for the measure ofthermal properties of fluids, according to the claim 44, characterizedby being the source of exclusive feeding, preferentially of the typetoggled, with multiple exits of continuous current and with independentfuses for each block of the referred system of measure and control. 52-system for the measure of thermal properties of fluids, according to theclaim 1, characterized by being the system of composed microprocessingfor a central processing unit, a recording unit and reading of data, ascreen, a mini-keyboard, a mouse, a feeding source, a plate or circuitwith multiple entrances and analogical exits and plate of synchronizeddetection. 53- system for the measure of thermal properties of fluids,according to the claim 52, characterized by being the central unit ofprocessing a commercial processing board with bus type ISA/PCI, or asystem commercial standard miniature MOP 104 with hard disk in solidstate, or a microprocessed system exclusively dedicated to accomplishthe operational functions of the system, for possessing as minimumspecification a frequency of 133 MHz for the processor, 16 Mb of RAMmemory and hard disk with 100 Mb of memory. 54- system for the measureof thermal properties of fluids, according to the claim 52,characterized by being the recording unit and reading of data a flexibledisk drive 3½″, or zip, or of CD. 55- system for the measure of thermalproperties of fluids, according to the claim 52, characterized by beingthe screen preferentially of the type TFT 6×5″ colorido or of liquidcrystal and that it allows the clear visualization of the graphs anddata of the measures. 56- system for the measure of thermal propertiesof fluids, according to the claim 52, characterized by being theprogrammable mini-keyboard, to have at least 44 keys, could be of thetype membrane or of buttons. 57- system for the measure of thermalproperties of fluids, according to the claim 52, characterized by beingthe mouse of the common type, linked to the serial port of the plateCPU, or to be preferentially of the type trackball, being in thisbuilt-in case in the own console of the keyboard. 58- system for themeasure of thermal properties of fluids, according to the claim 52,characterized by being the source of feeding of the type toggledcommercial, for PC and being exclusively for the feeding of themicroprocessing system. 59- system for the measure of thermal propertiesof fluids, according to the claim 52, characterized by being the plateor circuit with multiple entrances and analogical exits a commercialplate or a dedicated circuit that it is necessary only in the modalitiesof accomplishment of the system for measurement of thermal properties offluids in that the functions carried out by the system of measure andcontrol be executed through a program. 60- system for the measure ofthermal properties of fluids, according to the claim 52, characterizedby being only the plate of synchronized detection a commercial platethat is necessary in the modalities of accomplishment of the system formeasurement of thermal properties of fluids in that the function ofsynchronous detection, carried out by the system of measure and control,it be executed through a program. 61- system for the measure of thermalproperties of fluids, according to the claim 1, characterized by beingthe movable probe constituted by a main cylindrical tube, a cannon ofdiode laser or radiation source, a cover, a secondary tube, a slipperytube, a disk of sustentation of the sensor, a protection hose and ascouring pad. 62- system for the measure of thermal properties offluids, according to the claim 61, characterized by being the maincylindrical tube the place for the lodging of the cannon of diode laseror radiation source, for being endowed with thread in the previousextremity for the fitting of a cover, for being endowed with thread inthe subsequent extremity for the fitting of a longer secondary tube. 63-system for the measure of thermal properties of fluids, according to theclaim 61, characterized by being the cannon of diode laser or radiationsource a metallic tube, preferentially of steel, in whose interiorlodges a diode laser endowed with focalization system, or sourceradiation modulable, or source heating modulable, could be such sourcesa small incandescent lamp, or the direct heating generated by aconnected resistance to a variable source, or a thermoelectrical element(Peltier) that is in direct contact on the blackened surface of the diska cannon. 64- system for the measure of thermal properties of fluids,according to the claim 61, characterized by being the cover,preferentially made of brass, for possessing clamp of the type thread,for possessing a hole for the exit of a cable multi-roads, for thepassage of the signal drivers and of necessary feeding to the operationof the movable probe. 65- system for the measure of thermal propertiesof fluids, according to the claim 61, characterized by being thesecondary tube preferentially made of steel, for possessing in thesubsequent extremity a disk of aluminum with black covering in the facegone back to the interior of the tube, for possessing in the previousextremity a segment rosqueado for connection to the main cylindricaltube. 66- system for the measure of thermal properties of fluids,according to the claim 61, characterized by being the slippery tubepreferentially made of steel, for concentrically to work together on thesecondary tube through slippery joining, for possessing in thesubsequent part a base in disk form that possesses three set stemsdisposed in triangle, and in whose extremities adapt the disk ofsustentation of the sensor. 67- system for the measure of thermalproperties of fluids, according to the claim 61, characterized byconsisting the disk of sustentation of the sensor of two put uponcircular disks, a previous and other subsequent, for they be madepreferentially starting from a circuit plate printed with only face ofcopper, for they possess a wide central hole for the exhibition of thesensitive area of the sensor element, for they possess three holesdisposed in triangle for the passage of the fixation screws thatyou/they maintain the two united disks, for they possess other threeholes disposed in triangle and defased of 30 degree in relation to thethree previous holes, and the three holes defased are for the passage ofthe three stems of the base in form of disk of the slippery tube, forthey possess in one of the faces a copper electrode in ring form andthat it accompanies the whole outline of the wide central hole, forpossessing the copper ring a lateral derivation in appendix form thatextends from the border of the ring to the periphery of the disk in thesense of the ray and whose extremity is welded to the threads of thesensor element. 68- system for the measure of thermal properties offluids, according to the claim 61, characterized by being the protectionhose preferentially made of flexible material, resistant to the waterand solvents, for being of the folding type in order to not to impedethe relative movement between the slippery tube and the secondary tube.69- system for the measure of thermal properties of fluids, according tothe claim 61, characterized by being the scouring pad preferentiallymade of teflon, for possessing three holes for the passage of the threeextremities threaded of the three stems of the base in form of disk ofthe slippery tube, for to cover and to provoke the stretching of one ofthe faces of the sensor element. 70- system for the measure of thermalproperties of fluids, according to the claim 1, characterized by beingthe inherent resident software to the statement system and beingconstituted by exhibition module, adjustment module, conformity moduleand conformity grating. 71- system for the measure of thermal propertiesof fluids, according to the claim 70, characterized by being theexhibition module a program written in compatible language with theoperating system of the microprocessed system, for being the main screenof presentation of the resident program, for exhibiting graphs inprocess in real time of a measure, or of previous measures, be ofthermal property, or still any greatness or parameters that the userwants to correlate with some thermal property, for presenting as optioninherent pattern to the program two orthogonal axes, being the graduatehorizontal axis in time and the axis vertical graduate in the greatnessto be measured or visualized, for disposing for the user, several othertypes of exhibition of graphs that you/they are not the Cartesian, formaking available, in specific and fixed fields of the screen, the nameof the file of the measure in process, the value of the instantaneousmodule of the signal of the detector, the instantaneous value of theproperty thermal measure, the value of the real component of the signalof the detector, the value of the component imaginary of the signal ofthe detector, the value of the phase, the modulation frequency andelapsed time of the measure, for making available for the user menuoptions with functions to begin a measure, to select files, to name newfiles, to turn off files, to turn off graphs of the screen, to choosethe color or the symbol with that a graph or graphs of differentmeasures can be exhibited in the screen, for making available options toconfigure the interval of time among the acquisitions of the points ofthe measure, to program the total time of duration of the measure, theinferior limit and the superior of the vertical scale of the graph, forpossessing a function that allows to the user the access to the one newscreen and the group of functions belonging to the module foradjustment, for possessing a function that when worked after the end ofa measure, he/she draws in the screen a graph theoretical overlapped tothe graph of the measure, made calculations through an appliedinteractive process to a mathematical model defined previously by theuser, in an option of the module for adjustment, and that better it isadjusted by the criterion of minimum mistake, to the group of valuesthat represents the graph of the measure. 72- system for the measure ofthermal properties of fluids, according to the claim 70, characterizedby being the adjustment module a program written in compatible languagewith the operating system of the microprocessed system, for being asecond presentation screen, for possessing an option that allows to theuser to insert and to store expressions mathematical, defined or createdby the same, for including a group of parameters, also defined for theuser, and that through an interactive process, they converge for stableand defined values, for allowing to the user to test and to makecalculations through the said mathematical expressions, a certainphenomenon in function of the monitoring of a thermal property, for topossess an option that draws in the screen the graph resulting from thecalculation of the model and exhibit the correlation degree obtainedwith the same, also making possible the visual comparison between thegraph or points of the measure and the resulting model, for possessingas option inherent pattern to the program, a simple exponential model ofvariation of the thermal diffusivity in function of the time, todescribe evaporation phenomena, diffusion of gases, volatilization orgaseous emission of a sample. 73- system for the measure of thermalproperties of fluids, according to the claim 70, done characterize bythe conformity module to be a program written in compatible languagewith the operating system of the microprocessed system, for a thirdscreen of presentation of the program to be, for possessing as optioninherent pattern, a graphic screen with a horizontal axis for thethermal diffusivity α and a vertical axis for the constant ofexponential decline τ, by the values of the and t be made calculationsthrough a simple exponential model of variation of the thermaldiffusivity in function of the time, and does what in most of the cases,be to describe evaporation phenomena, diffusion of gases, volatilizationor gaseous emission of a sample, for possessing a function that allowsto the user the choice of the limits superior and inferior of each oneof the axes of the graph, for possessing windows in fixed places, thatyou/they allow the selection of the files of the measures whose thethermal diffusivity and the constant of exponential decline should bemade calculations, for possessing a window where the user should informto the program the distance between the sensor and the thermal wavescannon, for possessing two windows that exhibit the numeric values ofthe diffusivity and of the constant of exponential decline obtained fora certain measure, for possessing a function to make calculations and todraw in the screen the point, or the representative points of thermaland constant diffusivity of decline for the selected files, forpossessing a function to exhibit the report of all of the points thatyou/they have been calculated by the statement module, for possessingfunctions to clean the screen, to leave the program, to select theseveral conformity grating and for possessing a function to gage acertain conformity grating. 74- system for the measure of thermalproperties of fluids, according to the claim 73, characterized by beingthe conformity grating an inherent function to the conformity module,for making available a group of empty fields, us which the user can nameand to store a specific type of grating that is calculated for a groupof sample of a same type, for being represented graphically in thescreen by an area square or rectangular whose borders are defined forstatistical calculation, that you/they take into account the average andstandard deviations of the group, for indicating, of the qualitativepoint of view, the presence of no conformity in substances or samplesthat when measures, possess a pair of values of thermal diffusivity andof decline constant, whose position locates out of the limits of thesaid grating, for possessing a function that allows a third variable, orproperty and a mathematical model to be introduced and stored by theuser, so that the said variable is associated to each one of the pairsof values of the samples used to compose a certain grating, forproviding to the user a quantitative way to determine the numeric valueof the variable or of the property that one want to measure, for takinginto account the coordinate of a point on the plan of the graph and fordividing the plan of the graph in colored areas or in lines that possessas common characteristic the same numeric value of the variable or ofthe property in study.